It's generally a good idea to push the neck to position anyway and use the rod(s) to hold it in place.
(Unless they're dual-action ones.)
This chap explains the reasoning.
Ric documentation used to say bend it over your knee, but using a bench and clamps is probably a bit more refined.
On a Ric, keep both roughly in-step, ie. don't do all on one and have the other loose.
Also, on a RIc, press on the fretboard (at the 1st fret), not on the headstock (since you've got the TRC off, you can see there's not a lot of wood there to be pushing against).